This invention relates generally to methods and apparatus for delivering liquid solutions to treatment sites, such as in connection with periodontic procedures and, more particularly, to irrigation systems and methods for delivering a selected one of multiple liquid solutions to a treatment site.
The advantages of irrigation as a viable periodontal treatment are well documented. Irrigation systems are known for delivering a liquid solution to a treatment site which include a reservoir of the solution connected to an inlet side of a pump. A handpiece having an applicator tip is connected to the outlet side of the pump. The solution is delivered in a steady stream or in a fine pulsing jet through the handpiece to the treatment site. Such conventional periodontal irrigators are available, for example, from Vipont Laboratories of Fort Collins, Colo. under the trademark "Viajet" and from Teledyne Industries of Fort Collins, Colo. under the trademark "Water-Pik." Also, see U.S. Pat. No. 4,793,807 issued Dec. 27, 1988 to A. Friedman, et al.
Conventional irrigation arrangements have several deficiencies. One drawback is that conventional irrigation systems generally do not provide the opportunity of easy selection among several irrigant solutions. More particularly, different irrigating solutions are currently being used in the treatment of different periodontal conditions. For example, hydrogen peroxide solution is preferred for the removal of loose organic debris, zinc chloride is used to reduce inflammation, sodium fluoride is useful in the desensitization of tooth structure, and stannous fluoride and chlorhexidine digluconate are used in the reduction of bacterial concentration, including motile forms and spirochetes which are believed to cause periodontal disease. However, most available periodontal irrigation systems include only a single solution reservoir comprising an open-topped tank into which a quantity of solution is supplied. If circumstances require the use of a different treatment solution, either with the same or a subsequent patient, the solution remaining in the tank is usually discarded and the tank must be cleaned and refilled with the new solution. This procedure is time-consuming and costly, not to mention messy.
Another disadvantage of conventional irrigation arrangements of this type is that the irrigating solution can become contaminated since the solution generally flows in an open fluid system. For example, contaminants can enter the irrigation solution supply through the open top of the solution reservoir tank. Furthermore, the irrigating solution comes into contact with various components as it flows through the system which may be sources of contamination. For example, piston and diaphragm-type pumps must contact the solution, as do conventional heating elements in arrangements in which the solution is heated before treatment for the comfort of the patient. It is also possible for the handpiece to overheat where the heating element is situated in the handpiece.
At least one arrangement has been suggested which is adapted to enable a rapid selection from multiple irrigating solutions. In particular, an arrangement is disclosed in U.S. Pat. No. 4,215,476 issued Aug. 5, 1980 to A. Armstrong which includes a plurality of solution reservoirs, each comprising a quantity of a respective irrigating solution sealed within a flexible-walled bag, a handpiece for delivering a selected one of the irrigating solutions to the treatment site, and a selective coupling device for fluidly coupling the handpiece to a selected one of the irrigating solution reservoirs. The solution-filled bags are situated within a remote container over which a closure is secured to create a gas-tight enclosure. The interior of the enclosure is pressurized to a preset level and as this pressure acts on the flexible walls of the solution reservoirs, the selected irrigating solution is caused to flow from its reservoir to the handpiece.
This multiple irrigating solution arrangement, although permitting a rapid selection of one of several available irrigating solutions, has significant disadvantages. For example, it is not possible to quickly verify during a treatment that the irrigating solution being administered is the one desired. The user must rely on memory to identify the treatment solution. Moreover, there is always a danger that an incorrect irrigant solution may be supplied because of a mistake in set-up and assembly of the apparatus.
Other disadvantages of this arrangement result from the use of a pressurized container to "pump" the selected solution towards the handpiece. For example, the selected irrigating solution cannot be dispensed from the handpiece as a pulsed jet, or at a uniform pressure and volumetric flow rate. Rather, the solution is supplied in a continuous stream which is not as effective as a pulsed jet, and at a relatively varying rate. Moreover, it is necessary for the container in which the pressurized solution reservoirs are enclosed to be situated proximate to a source of pressure. This will seriously reduce the flexibility of the system, at least insofar as location and movement. The use of a pressurized, sealed container limits the number of available solution reservoirs. Furthermore, the arrangement makes no provision for heating the selected irrigating solution.